The chipset chosen to be used on Quad FX platform was nForce 680a SLI from NVIDIA. The features described below are from this chipset, not being set by the Athlon 64 FX-7x processors. We don’t know if AMD plans to use a different chipset with this platform.

We commented previously that each Athlon 64 FX from 7x series has three HyperTranspor busses. One was used for the communication between the two processors but instead of using only one HyperTransport to connect the CPU to the chipset – and from the chipset to the other peripherals found on the PC that we didn’t mention so far, like the video card and the hard disk drive – AMD and NVIDIA decided to use two busses, each one connected to a nForce 680a SLI chip, allowing an amazing number of features

On Figures 3 and 4 you can see the block diagram of Quad FX platform showing all features available.

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Figure 3: Quad FX plaform block diagram (AMD’s slide).

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Figure 4: Quad FX plaform block diagram (NVIDIA’s slide).

The main features from Quad FX platform using NVIDIA nForce 680a chipset are:

• Two x16 PCI Express slots working at x16 and supporting SLI mode
• Two x16 PCI Express slots working at x8 and not supporting SLI mode
• One x1 PCI Express slot
• One regular PCI slot
• Four Gigabit Ethernet ports
• 12 SATA-300 ports
• Four ATA-133 ports
• 20 USB 2.0 ports
• RAID (0,1,0+1,5, JBOD)
• 7.1 high-definition audio

Even though QuadFX motherboard has for x16 PCI Express slots two of them work at x8. Besides that, only the ones that truly run at x16 support SLI mode. With four video cards installed, you can have a total of eight displays connected to the PC, four of them connected to two video cards running under SLI mode.

The first Quad FX-compatible motherboard released was ASUS L1N64-SLI WS. You can see the details of this motherboard in Figure 5.

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Figure 5: ASUS L1N64-SLI WS motherboard.